Watermelon adds a ton of hydrating water as well as A and B vitamins.
Once you've mastered the granita technique, you can make this dessert in a variety of different flavors, including the classic espresso.
Combine the sugar and 3 ounces of water in a saucepan and boil for about 1 minute, until the sugar has dissolved. Remove from heat and let cool. Cut the watermelon flesh into cubes and puree in a blender or food processor until smooth. Strain through a fine-mesh sieve and stir in the sugar syrup and rose water. Transfer the mixture to a shallow, metal container.
Freeze for about 4 hours, stirring with a fork about every 30 minutes to prevent large ice crystals from forming. Scoop into chilled glasses and serve.